DETERMINATION OF GLYCOSYLATION SITES OF GLYCOPROTEINS

University Of Georgia (Uga), Athens GA

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Abstract

We have developed a new method that permits matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and tandem MALDI (MALDI-MS/MS) spectra to be obtained on magnetic sector-based mass spectrometers. Our approach is based upon development of a new family of MALDI matrices. The novel feature of the new matrices is that they are viscous liquids and thus have self-healing surfaces. This property provides a long-lasting and reasonably constant flow of ion currents from picomole quantities of analyte. MALDI-magnetic sector spectra can be obtained, therefore, even though a non-integrating point detector is used. This is the first time that MALDI has been demonstrated on a sector-based MS without significant modification to the instrument. The ability to perform MALDI on sector-based instruments is expected to play a key role in our project involving the structural analysis of oligosaccharides by MS/MS of their alkali metal adducts. Because MALDI is approximately 1,000 times more sensitive than fast atom bombardment (FAB), sample requirements for the proposed analytical scheme are significantly reduced. The ability to analyze these samples by MALDI has also made our proposed approach much less sensitive to the amount of alkali salt in the sample, greatly facilitating our MS/MS study.